Restore Brush Rotation - Shark Navigator

This is our eight year old Shark Navigator NV42 vacuum cleaner. The roller in the head does not spin when the switch is set for it to spin. A video at YouTube says that is definitely caused by hair that has wrapped around the shaft in the bearings. That diagnosis does not apply to this model for two reasons. The end of the roller is not removable as shown in that video. And, the head on this machine is designed with seals that keep hair from entering the bearing area. Before you take the head apart see the next step.

Do not disassemble the head unless you really need to do so. But, I did include information for dismantling the head for those who need to dismantle it. See the last paragraph in this step for how I tested the head.

The first photo shows the underside of the machine’s head. Holes in which screws are located are quite easy to see. Two small screws retain the wheel axles and do not need to be removed if you want to open the head. But, there are two screws behind them and you need to remove those.

See the second photo. Two screws cannot be seen. Use a very small screwdriver to pry the axles on the very small wheels from their mounts as shown. The screwheads are behind these small rollers.

I did not take any photos while I had the head open. But, here is a description of what is inside. Notice the screw socket in the center of the head. Let that be an orientation point, like the center of a clockface. The motor and belt are located at 3 o’clock. The circuit board is located at 9 o’clock. There is a micro switch at 11 o’clock. The brush roller will not turn if the handle is vertical. The micro switch locks the motor circuit out. The handle needs to be brought back so it is at an angle to the floor before the motor can run. Parts like the motor, circuit board, and micro switch are available for sale at eBay.

The motor is a small 120 volt motor with a commutator and brushes. I wanted to clean the commutator, but it is difficult to reach the commutator and clean it effectively. Dismantling the motor is almost impossible. The commutator was not very dirty, even after eight years. I decided to leave well-enough alone.

The third photo shows the quick disconnect joint that allows removing the head. When assembled, make certain these two pieces are firmly and fully snapped together. It so happens this was the problem on our vacuum. This junction was not completely snapped together and the motor in the head did not receive power.

The fourth photo shows a test wire I used to see if I could make the motor run. When I did the test I used two hands better to control each wire. There is reason to use only one hand, though. If insulation on the wires were faulty, a flow of electricity could cross your chest, and that can easily be fatal. As soon as power went to the head terminals on the quick junction the roller brush in the head roared into life at full speed. Nothing was slowing the roller bearings, like hair.

The strain relief was failing. Soon bare copper would be exposed. See the red circle in the first photo. I made a new strain relief from some steel tubing. I made kerfs and bent the tubing. Then I welded the kerfs closed to make a permanent curve. I welded tabs to the tube to fit down into recesses in the plastic casting. I filled the recesses with molten hot glue. When it had cooled and hardened my strain relief was very sturdily mounted. But, I made an additional adjustment. I added a moderately stiff spring to complete the strain relief. See the second photo.

I did make one error. I failed to notice the small attachment holder below the strain relief. Now a small brush for the end of the suction hose does not fit there.

The photo shows the terminals on the rocker switch. It has three positions: off, suction motor, and suction motor with head roller brush in combination. I decided to install a new switch as a precaution because the original switch has eight years of wear on it. It also felt a little mushy, even though it tests good. This Shark switch is available for around $12 delivered at eBay. Amazon also has it. A local vacuum repair shop might sell one to you, too.

The terminal at the bottom of the photo is the black wire that is the line. The terminal at the upper left is the thicker black wire that powers the suction motor. The terminal at the upper right powers the motor in the machine head and is blue. I added a short piece of wire to each wire to lengthen it just a little. The original length was a little short, and some of the spade connectors pulled off when I removed the original switch. It is a good idea to test the switch function before closing the halves of the machine.

I did need to cut the label on the back in half along the seam and I did need to remove the chrome Shark emblem on the front.

Our vacuum now runs reliably.